A reference signal for an analog to digital converter (ADC) often becomes marred by noise during the analog to digital conversion process. A filter circuit to shunt the noise to ground can reduce the noise. However, the filter circuit for shunting the noise frequently increases a settling time of the ADC during ADC calibration.
What is needed is an apparatus and method to reduce the settling time of the ADC during ADC calibration as well as overcome other shortcomings noted above.